Air compressing system



' Jan. 5, 1932. HT. HUNTER AIR COMPRESSING SYSTEM 5 Sheets-Sheet 1 Filed Nov. 3, 1928 FIG I.

i INVENTOR: Henberz? Tfizmzez;

ATTORNEYS.

WITNESSES j Jan. 5, 1932. H. T. HUNTER AIR COMPRESSING SYSTEM 5 Sheets-Sheet 2 Filed Nov. 3, 1928 INVENTOR:

Herbefi T Hwziez; BY 7 W ATTORNEYS.

Jam 5, 1932. H. T. HUNTER AIR COMPRESSING SYSTEM Filed Nov. 5, 1928 6 Sheets-Sheet 3 INVENTOR: Hwberfi Tfiuzziez;

ATTORNEYS:

/A/////ZW@ WITNESSES Patented Jan. 5, 1932 UNITEDVSTATEST PATENT OFFICE HERBERT ,T. HUNTER, OF CATONSVII LLE, MARYLAND, ASSIGNOR TO DOUGHNUT production of compressed air MACHINE CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK AIR comrnnssme SYSTEM Application filed November 3, 1928. Serial No. 317,078.

This invention relates to air compressing systems intended for the generation and maintenance of a static head of air, as distinguished from systems designed for the in large quantities. A system of the specific type referred to, although adaptable to other purposes, is particularly useful with apparatus for cooking articles like doughnuts as in- 10 stancediin U. S. Patent 1,492,542 granted to John G. Bergner, under date of April 29, 1924. In such apparatus, the static head of compressed air is relied upon to effect extrusion of plastic or dough through intermittently actuated die mechanism to form the raw articles which are to be cooked. Obviously, the size of the extrusions under these conditions is directly dependent upon the force behind the dough; but due to vacillations of a slow speed generating pump, considerable difliculty has been experienced heretofore in holding the compressed air head at a constant pressure with consequent lack of uniformity in the articles.

My invention is directed toward overcoming the recited drawbacks; and this desideratum I attain through provision of .a simple, 'efiicient and reliable compressing system capable of ready adjustment to operate at any pressure predetermined upon, and of accurately maintaining such pressure evenly and constantly, notwithstanding dwindling of the supply of material being acted upon.

In the drawings Fig. I is an illustration partly in side elevation and partly in vertical section of a doughnut machine equipped with the air compressing system of my invention.

Fig. II is a plan section of the machine taken as indicated by the arrows II-II in I Fig. I.

Fig. III is a detail view mostly in section showing novel control means associated with my invention. V

Fig. IV is a detail view on a larger scale showing the details of the pump by which the air is compressed.

Fig. V is a fragmentary detail section taken as'indicated by the arrows VV in Fig. IV; and,

Fig. VI is a transverse section taken as indicated by the arrows VI-VI in Fig. IV. The doughnut machine herein illustrated for the purposes of exemplifying one practical use of my improved air compressing system is, generally speaking, of the type disclosed in the United States patent hereinbefore referred to in that it comprises a circular receptacle 10 for hot cooking liquor in which the articles to be cooked are slowly advanced afloat by an intermittently rotating cellular progressing means 11, and, after lapse of a predetermined period essential to proper cooking, ejected onto a discharge chute 12. The machine is driven by an electric motor 13 which is connected by a belt 14 to the high speed shaft 15 of a reduction gearing device comprehensively designated by the numeral 16. Through suitably interposed gear elements shown in Fig. II, slow motion is communicated to the depending vertical shaft 17 of the progressing means 11 in rotating the latter intermittently for the purpose aforesaid. The machine further comprises a dough magazine 18 which is supported above the cooking receptacle 10, and, in the present instance, located exteriorly of the protective housing 19 of the machine. Under a static head of the compressed air, the raw dough is forced through an annular outlet of a die means 20 at the bottom of the so magazine 18, said die means embodying a sleeve 21 which is intermittently operated to shear over a concentric disk 22 in severing successive extrusions of the plastic. Intermittent reciprocating motion is imparted to 815 the sleeve 21 by a yoke lever 23 connected, through a rod 24 with an arm 25 in the machinery compartment beneath the receptacle 10 within the housing 19, for actuation by a cam 26 associated with the gearing device 16.

In adapting my invention to a doughnut machine of the kind briefly outlined, I provide a pump such as shown at 30in Figs. I and II and detailed in Figs. IV, V and VI. The cylinder 31 of this pump is secured, for convenience, to the side of the casing of the speed reduction device 16 by bolts 32; and in this instance is disposed at an angle for the sake of economizing on head room within the bottom or machinery compartment of without oscillatory movement of its cylinder 31 andwithout attendant vibration. The operation of the pump is further eased and stabilized by virtue of a prolongation 34a of the rod 34 beyond 'thelower end of the piston, said prolongation being guided in a charges through a better balance the operation of 30 is by way tubular'bearing 39 forming an axial extension of said cylinder. To relieve compression within the tubular extension 39, the piston rod prolongation 34a is provided with a longitudinal duct 41 (Fig. V) which dislateral port 42 into the clearance space43 beneath the piston 33 within the cylinder 31. The pump 30 is of the single acting type, that is to say, compresses air only during the down stroke of the piston, relief being had incidental to the up stroke through radial ports 44 at the top of the cylinder 31. The size of the ports 44 is such that a cushioning effect is obtainedduring the up stroke of the piston 33, thereby to the pump 30 and minimize vibration. As shown in Figs. IV and VI, the space 43 beneath the piston 33 communicates, through a duct 45, with an I inlet 46 that is fitted with a check valve 47 wherein a closure ball 48-is yieldingly urged toward its seat by a'helical spring 49. Discharge ofthe compressed air from the pump of a port 50 fitted with a similar check valve 51 which is held shut during the intake strokes of the piston 33 by a spring 52 acting on its closure ball 53. The substantially non-pulsating stream of compressed airgenerated by the pump 30- as a consequence of-operation at high speed, is conducted by a pipe '55 leading from the valve 51, to an equalizing tank-56 (Figs. I and II) located in the machinery compartment beneath the receptacle 10.

From this equalizing tank 56 the compressed air is in turn conducted, through a pipe 57, to a fitting 58 secured to the roof of the machine, see Fig-I, andfrom thence intoithe dough reservoir 18 through a flexible tube'59 connecting with a nipple 60 on the removable reservoir cover 61, which, as shown, is secured air tight by means ofv a yoke 62 with 'a clamp screw 63.

that the same has an elongated horizontal tubular body portion w1th one end turn'ed'up as at- 65 for connection of the flexible tube 59,

at high speedsmaintaining a static head of and bored transversely to afford a seat for a plug valve 66 with a manipulating handle 67. This valve 66 is kept open normally, and is provided as a means to shut off the air flow during the intervals required in charging the dough receptacle 18. A vertical boss 68 at the opposite endof the fitting 58 is axially bored to take a needle valve 69 which has threaded engagement at 70 for the purpose of adjustment of its lower tapered end 69a in respect to the reduced portion 68a of the borecommunicating direct into the hollow of the body of the fitting 58, to control bleeding of air through a 'lateral'port 71 that discharges into the'atmosp here. At the top, the

needle valve stem carries a knurled adjusting seen that any desired constant static pressure may be maintained in the system with preassurance of uniformity in the size of the extrusions released by the die mechanism 20 atthe bottom of the dough magazine 18. As an aid in making such adjustments of the needle valve 69, I employ a pressure gage 73 for connection of which provision is made on the fitting 58 in the formof a boss 7 4 located centrally between the ends 65,68. Toenable securing of the needlevalve '69 against displacement after the desired pressure adjustment has been obtained, I provide a jamb piece 75 which occupies a lateral opening of the boss 68,, and which is urgedinwards against the valve stem 69 bya thumb screw 76. This thumb screw 76 has threaded engagement in a block 77 fixedly attached to the corresponding side of the boss 68. The block 77 also affords slide bearingfor the stem '7 8 of a valve 79 whereby the bleed port 71 can be held closed temporarily, through push of the thumb, until the pressure builds up in the system upon opening of the plug valve 66 after recharging the dough magazine 18. Upon being freed subsequently, the push valve 7 9 is automatically retracted to the normal position-illustrated by a spring 80, thereby permitting escape of air through the bleed port 71.

From the foregoingit will be apparent that I have provided an organization capable of air under absolutely constant pressure, irrespective of gradual depletion of the dough supply within the magazine 18. It will moreover be seen that through careful regulation of the controlling needle valve 69, the pressure can be varied within fine limits to predetermine proportionately small variations in the size of the extrup I sions intermittently released by the diemeans RGfGIIIIIgIIOW to Fig. III wherein the it- 20 ting 58 is illustrated in detail, it will benoted Although I have herein shown and described my invention in connection with a commercial form of doughnut cooking apparatus, it can obviously be put to other uses;

and certain of the subjoined claims are therefore to be broadly construed with this thought in mind.

Having thus described claim:

1. A high speed pump for maintaining a static head of compressed air, in the dough magazine of a doughnut forming device, comprising a piston with means to stabilize the reciprocative movement thereof, and means to direct counter-compressive force from the stabilizer means on the forward stroke of the piston to predetermine substantially constant delivery of compressed air devoid of pulsation to the magazine aforesaid.

2. A pump for maintaining a static head in air compressing systems, means to operate the pump at a constant high speed, means to stabilize the reciprocative movement of the pump piston, and means to divert countercompressive force from the stabilizer means on the forward stroke of the pump piston whereby the compressed air is delivered substantially devoid of pulsation.

3. A pump for maintaining a static head in an air compressing system, means to operate the pump at a constant high speed, a stabilizing prolongation from the pump piston guided by a tubular bearing forming an axial extension of the pump cylinder, and means to divert counter-compressive force from the stabilizer prolongation on the forward stroke of the pump piston whereby the compressed air is delivered substantially devoid of pulsation.

4. A pump for maintaining a static head in an air compressing system, means to operate the pump at a constant high speed, a stabilizing prolongation from the pump piston guided by a tubular bearing forming an axial eX- tension of the pump cylinder, said prolongation having a longitudinal duct in communication by way of a lateral port into a clearance in advance of the pump piston, and means to divert counter-compressive force from below the stabilizer prolongation on theforward stroke of the pump piston whereby the compressed air is delivered substantially devoid of pulsation.

5. A pump for maintaining a static head in an air compressing system, means to operate the pump at a constant high speed, a stabilizing prolongation from the pump piston guided in a tubular bearing forming an axial extension of the pump cylinder. said my invention, I

' prolongation having a longitudinal duct in communication by way of a lateral port into a clearance in advance of the pump piston, and radial relief ports in the rear end of the pump cylinder; whereby, on the return stroke of the piston, the pump is better balanced, vibration is minimized, and the compressed air delivered substantially devoid of pulsation. 6. A pump for maintaining a static head in an air compressing system for effecting displacement of formations of plastic means whereby said pump is operated through direct co-ordination with a shaft running at a constant high speed, a stabilizing prolongation from the pump piston guided in a tubular bearing forming an axial extension of the pump cylinder, said prolongation having a longitudinal duct in communication by way of a lateral port into a clearance in ad- Vance of the pump piston, and radial relief ports in the rear end of the pump cylinder, whereby on the return stroke of the piston, the pump is better balanced, vibration is minimized, and the compressed air supplied to the plastic substantially devoid of pulsation.

In testimony whereof, I have hereunto signed my name at Ellicott City, Md, this 25th day of October, 1928.

HERBERT T. HUNTER. 

